Steam-boiler



(N0 Model.)

J. A. CALDWELL.

STEAM BOILER. No. 407,888.

Patented July 30,1889.

N. PETERS. Phcwlflhognphnr, Washington. D. C.

UNITED STATES ATENT FFICE.

JOHN A. GALDIVELL, OF BAY RIDGE, NE\V YORK.

STEAM-BOILER.

SPECIFICATION forming part of Letters Patent No. 407,888, dated July 30, 1889.

Application filed December 17, 1886. Serial No. 221,828. (No model.)

To all whmn it may concern:

Be it known that 1, JOHN A. CALDWELL, a citizen of Great Britain, and a resident of Bay Ridge, in the county of Kings and State of New York, have invented a new and useful Improvement in Steam-Boilers, of which the following is a specification.

My invention appertains to sectional or wator-tube boilers in which the tubes are arranged in a nest, preferably of three to each header or box, a series of such boxes being interconnected to form the water-legs of the boiler.

My invention comprises an improved device for securing the covers to the said headers or boxes, so that a very high pressure of steam may be maintained without risk of leaking and without requiring any steam joints around the fasteningbo1ts; no bridges or other interior castings will interfere with the expanding of the tubes and attaching them to the boxes, or with a free circulation of water in the boiler; a clear space will be left inside for access to the interior tubes when the covering-plate is off; the cover and fasteningbolts are all attached to the outside of the box, making it easy to adjust and replace the packing of the cover; also, the construction of the superheater and the construction to allow of cleaning the circulating-tubes, as will be hereinafter fully described, and specifically pointed out in the claims, reference being had to the accompanying drawings, in which- Figure 1 represents a side elevation, partly in section, of a water-tube boiler constructed according to my present invention. Fig. 2 is a front view, partly in section, on the line 00 a; of Fig. l, of the steam and water drum, the superheater-header, and the upper part of the water-tube headers. Fig. 3 is a front or end view of one of the water-tube headers with cover attached. Fig. at is an edge view of the same, seen in the direction of arrow 1 in Fig. 3. Fig. 5 is a detail sectional view of the extension by which the rear upper header is connected to the circulating-tubes passing into the steam and water drum.

' H is the steam and water drum, and Q T the water-legs of the boiler, interconnected by the tubes F and secured by saddles to the drum H. At the lower end of the rear waterleg is the usual mud-drum N.

Instead of supporting the boiler by the mud-drum direct upon the foundation 0, I form or attach a projection M on the under side of the mud-drum, and support it by the said projection in a notch or otherwise upon the foundation, as shown in Fig. 1. By this means the mud-drum is kept up out of the soot, which. is more orless damaging under certain conditions and very corrosive in its Y action upon metals. For superheating the steam I arrange upon the upper front row-0f the regular headers D a header or box 0, and connect it by circulating-tubes A A with the steam-space of the drum H.

A row of tubes E connect the superheaterheader 0 with a drum G, arranged above the water-tubes F, and underneath the water and steam drum directly in the path of the heat from the furnace. This drum is connected by a pipe P, smaller than the pipes A, with the steam-space in the drum H.

The water-leg Q communicates with the water-space in thedrum H by nipples R,which pass through the superheater-header 0, being expanded and thus tightened in the upper row of headers D, the header 0, and the saddle l3. WVater-circulation at the inner end of the boiler is kept up by means of the tubes S, connected at their upper ends to the waterspace of the drum H, and expanded at their lower ends into a neck K, which is an extension of the upper row L of headers of the inneuwater-leg T. The object of connecting the water-leg T and the circulating-tubes S by means of the neck K is to getaccess through a removable plug or cover 70, opposite the lower end of each tube S, to clean the said tube.

The steam from the drum H passes by means of the tubes A into the header 0, and thence through the pipes E into the drum G, and thus gets superheated, the pipe P keeping up the circulation of steam through the superheater and drum H, and superheated steam being drawn off from the drum G by means of the pipe J. Ordinary saturated steam is taken through the nozzle I, entering from the side of the drum, as in Fig. 1. The safety-valve is, secured to a similar nozzle I, indicated by.the dotted circle in Fig. 1.

U is one of the headers or boxes containing, preferably, three tubes, arranged triangularly. These tubes are fastened by expanding them in holes through the back wall of the box U, the front wall at having one continuous opening through which free access is gained to the interior of the box and the three tubes F.

The side walls of the box U are smooth, as

-in similar headers heretofore made, and

through the upper and lower of them are made holes through which tubular nipples g are expanded, as usual, to connect the box to the two adjacent boxes.

The box U has no bridgesinside for the attachment of bolt-heads and the consequent obstruction of circulation of water and prevention of access to the tubes F; butthe space inside is perfectly clear.

At three points in the sides of the casting, near the front edge thereof, and intermediate to and alternating with the location of the centers of the tubes F are formed pockets with sockets 0, opening outward or through the side wall. These sockets c are wide enough to receive the head of the bolts 6, two opposite sides of the bolt-head being filed off even with the surface of the bolt-shank, and the head of the bolt being inserted from the outside through a slot d and then turned a quarter of a turn when the head has entered into the socket c, as in my pending patent application, Serial No. 217,941, filed November 4, 1886, and allowed December 1, 1886. In order to give room for the pockets in which the slot and sockets are formed, the side walls of the box are rounded off at f, so as to pre sent a convex surface toward the inside, as also stated in the application above referred to, thereby considerably strengthening the casting against expansion due to the pressure of steam.

V is the cover common .to the three tubes F and the intervening space, the cover being packed against a seat or planed edge on the casting, as in the application referred to. In my said application the cover is held by three bolts threaded into lugs in a plate separately secured to the box U, the said.

bolts pressing upon the cover in the centers of the three tubes F, thus distributing the pressure upon three bolts instead of one, as previously used.

I11 this present application the pressure is distributed on three bolts, which are the same bolts 6 by which the hexagonal plate was secured according to my said pending application, and which, in this case, pass directly through lugs at, one at the middle of each side of the triangular plate V, as shown in Figs. 3 and 4. If it is desired to add one more bolt, pressing upon the center of the plate V, this may be accomplished, as shown in Figs. 3 and 4, by a spider IV, secured through the ends of its three arms by the same bolts 6 by which the cover V is directly secured to the box U, and then threading through the center of the said spider W, a bolt or set-screw h inserted through the spider from the outside and pressing upon the center of the cover.

By superheating steam in the manner hereinbefore described I am enabled to produce a very high grade of steam,'and at the same time draw it off through the pipe J at a low point, thereby saving height in the boiler, which heretofore has been a great objection.

It will be seen that the bolts by which the cover is held do not pass through the opening or inner space of the box or header, and, consequently, do not need any packing to keep them steam-tight, with the accompanying liability to leak, as is the case in some other boi1ersfor instance E. J. Moores, No. 305,401, and J. L. Gill, Jr., No. 335,750.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is Y 1. In a sectional steam-boiler, the combination, with a box or header having tubes communicatin g with the same and an opening giving access to the said tubes, of a cover V, adapted to close the said opening and bolted to the said box from the outside by bolts passing through the said cover and the side castings at points outside of the said opening, substantially as and for'the purpose set forth.

2. Ina sectional steam-boiler, the combination,with a box or header having tubes communicating with the same and an opening giving access to the said tubes, of a cover V, adapted to close the said opening and bolted to the said box from the outside at points intermediate to the location of the said tubes by bolts passing through the said cover and the side casting at points outside of the said opening, substantially as and for the purpose set forth.

3. In a sectional steam-boiler, the combination, with a box or header having tubes coinmunicating with the same and an opening IIO giving access to the said tubes, and having exterior pockets adapted to receive and retain bolts e, inserted from the front of the said box, of a cover to close the said opening and having holes at its edge in front of the said pockets, and bolts 6, held by their heads in the said pockets and passing through the holes in the said cover, for the purpose of tightening the latter against the box without the use of steam-packing around the bolts, substantially as specified.

4. In a sectional steam-boiler, the combination, with a box or header having tubes communicating with the same and an opening giving access to the said tubes, and having exterior pockets adapted to receive and retain bolts 6, inserted from the front of the said box, of a cover adapted to close the said opening and having holes at its edge in front of the said spider having a bolt or set-screw h pressing upon the said cover V, substantially as specified.

5. In a sectional steam-boiler, the combination, with the header L and with the steam and Water drum H and circulating-tubes S, of the neck or extension K upon the said header, the said extension receiving the lower end of the said circulating-tubes and being provided opposite to the same With a removable plug or cover 7;, to gain access 'for cleaning of the said tubes substantially as specified.

6. The superheater consisting in the combination of tubes E, steam-drum G, receiving one end of the said tubes, header 0, receiving the other end of the said tubes, and steamcirculating pipes P and A, communicating with the steam-space in the steam and Water drum H, the upper headers D of thewvaterleg Qbeing connected by nipples R directly to the Water-space of the drum H, substantially as specified.

In testimony that I claim the foregoing as my invention I have signed my name, in presence of two Witnesses, this 16th day of December, 1886.

JOHN A. CALDWELL.

Witnesses T. M. CRossMAN, HELMER WEsTEEN. 

